An adjuster shown in FIG. 12 has been generally known as a belt length adjuster of this type. The adjuster includes a frame body 11, which has a substantially square shape with both side frames 11a and 11a and both connecting frames thereof 11b and 11b, and a support frame 12 for belt provided at a substantially central part of the inside of the frame body 11. An insertion space S is formed in both sides of the support frame 12, and a serrations or knurls 13 for slip prevention are provided on an inner side of each of both side frames 11a and 11a as desired.
The above-described belt length adjuster is used as shown in FIGS. 13 to 15. One end part of a belt B for goggles and the like is attached on the support frame 12, and the other end side of the belt B, which is folded back, is inserted upward into one of the insertion spaces S on both sides of the support frame 12, and, straddling the support frame 12, inserted downward into the other of the insertion spaces S and drawn out therefrom. Thus, shifting the position of the adjuster with regard to the belt B and changing the position where the belt is folded back enable adjustment of the length of the belt in use with the adjuster as stated above.
Another example of a known adjuster of the belt length is described in Japanese Patent Application, Laid-Open No. 2007-54347. As shown in FIG. 16, this adjuster has a frame body 21 having a substantially square inside space S and a slide body 22. The frame body 21 has opposing slide-contact frame parts 21a and 21a and opposing support frame parts 21b and 21b, these frames define the space S. The slide body 22 is loosely fixed to the support frame parts 21b and 21b in the inside of the frame body 21, and, supporting one end part of the belt 4, slidable toward either of the slide-contact frame parts 21a and 21a. One of the slide-contact frame parts 21a and 21a is provided with an exterior member 23 for slip prevention.
The foregoing belt length adjuster is used as shown in FIG. 17. One end part of the belt B is supported by the slide body 22, while the other end side is folded back, then inserted successively into the spaces S which are formed between the slide body 22 and each of the slide-contact frame parts 21a and 21a. Away from one of the slide-contact frame parts which stands in the side of the other end side of the inserted belt B, the slide body is slid toward the other of the slide-contact frame parts 21a. Thus the belt B is held between the slide body 22 and the other of the slide-contact frame parts 21a where the belt B can be fixed and engaged with respect to the frame body 21. On the other hand, releasing this holding engagement of the belt B therebetween enables the release of the fixed belt from the frame body 21, so that the adjustment of the belt length is achieved.
The above-described conventional belt length adjuster shown in FIG. 12 has a problem. Since a lower surface of the other end side of the belt B inserted into the insertion spaces S on both sides of the support frame 12 directly lies on top of and in contact with an upper surface of the one end part of the belt B attached to the support frame 12, and the contact area therebetween is large, which makes frictional resistance very large and makes it difficult to move the position of the adjuster and therefore to adjust the length of the belt.
The foregoing conventional belt length adjuster shown in FIG. 16 has another problem. One of the slide-contact frame parts 21a is provided with the exterior member 23 for slip prevention. Since the exterior member 23 is a separate member from the frame body 21, and needs to be annually wound around the slide-contact frame part 21a, the manufacture thereof is difficult and the manufacturing cost is high. Further, this belt length adjuster has a further problem. While the slide body 22 is provided to facilitate shifting the position of the adjuster, since the slide body 22 needs to be slid for shifting the position of the adjuster, such sliding is cumbersome and the adjustment of the belt length cannot be performed instantly.
Moreover, both of the above-described conventional belt length adjusters have a still further problem. When attaching one end part of the belt B to the support frame 12 of the frame body 11 or the slide body 22 of the frame body 21, it is necessary to insert the one end part of the belt B into the space S, wind it in a loop shape around the support frame 12 or the slide body 22, and sew the wound end to the belt body B, which requires cumbersome steps and is very inconvenient.
It is hence an object of the present invention to solve the above conventional problems, and to provide a belt length adjuster which enables easy and instant adjustment of the length of the belt, and moreover which is easily manufactured without a high manufacturing cost.
It is a further object of the present invention to provide the belt length adjuster which enables a simple attachment of one end part of the belt member to the frame body, thereby extremely easy attachment is achieved.